Inkjet printers are known. In conventional inkjet printers, ink is ejected in the form of a drop through a printhead (having a plurality of discharge devices and nozzles) and onto a receiver in ether a continuous or on demand manner. Conventional inks typically include a colorant (either a dye or a pigment) and at least a-solvent. The ink is stored for use in an ink tank or ink cartridge with the tank or cartridge being connected in liquid communication with the printhead in one of several known ways. In multiple color inkjet printers, the printer includes a plurality of these ink tanks or ink cartridges with each tank or cartridge including an ink having a distinct color or color shade.
Conventional inkjet printers have disadvantages. In order to achieve high image quality metrics (for example, high resolution images (images approaching 900 dots per inch)) while maintaining desired printer productivity (often referred to as throughput), printheads typically include large numbers of discharge devices that are frequently actuated. This limits the viscosity of the ejected inks. As such, the viscosity of the ink is usually lowered by adding solvents such as water, for example. The increased solvent content results in slower ink drying times after the ink has been deposited on the receiver. This, in turn, decreases printer productivity. Increased solvent content can also result in an increase of image defects (for example, image bleeding) which negatively affects image quality metrics, for example, image resolution.
Another disadvantage of conventional inkjet printers includes nozzles that become partially or completely clogged and, therefore unusable. Typically, this is caused by the collection of dried ink and/or the collection of debris (for example, paper dust, dirt, etc.) in and around the nozzle. To reduce this problem, solvents such as glycol or glycerol are added to the ink which can lead to the problems discussed above.
Another disadvantage of conventional inkjet printers includes using multiple color ink tanks or cartridges when multiple color images are desired. This increases the cost associated with multiple color printing because individual ink tanks or cartridges, with each tank or cartridge containing a distinct ink color, are necessary.
Technologies that deposit materials onto a receiver using gaseous propellants are known. For example, Peeters et al., in U.S. Pat. No. 6,116,718, issued Sep. 12, 2000, discloses a print head for use in a marking apparatus in which a propellant gas is passed through a channel, the marking material is introduced controllably into the propellant stream to form a ballistic aerosol for propelling non-colloidal, solid or semi-solid particulate or a liquid, toward a receiver with sufficient kinetic energy to fuse the marking material to the receiver. There is a problem with this technology in that the marking material and propellant stream are two different entities and the propellant is used to impart kinetic energy to the marking material. When the marking material is added into the propellant stream in the channel, a non-colloidal ballistic aerosol is formed prior to exiting the print head. This non-colloidal ballistic aerosol, which is a combination of the marking material and the propellant, is not thermodynamically stable/metastable. As such, the marking material is prone to settling in the propellant stream which, in turn, can cause marking material agglomeration, leading to discharge device obstruction and poor control over marking material deposition.
Huck et al., in WO 02/45868 A2, discloses a method of creating a pattern on a surface of a wafer using compressed carbon dioxide. The method includes dissolving or suspending a material in a solvent phase containing compressed carbon dioxide, and depositing the solution or suspension onto the surface of the wafer, the evaporation of the solvent phase leaving a patterned deposit of the material. The wafer is prepatterned using lithography to provide the wafer with hydrophilic and hydrophobic areas. After deposition of the solution (or suspension) onto the wafer surface followed by the evaporation of the solvent phase, the material (a polymer) sticks to one of the hydrophobic and hydrophilic areas. The solution (or suspension) is deposited on the wafer surface either in the form of liquid drops or a feathered spray.
This method is disadvantaged because deposition using a feathered spray requires that the wafer surface be prepatterned prior to deposition. Hence, direct patterning of the wafer surface is not possible because of the diverging profile (feathered) of the spray. Additionally, a wafer surface that has not been prepatterned can not be patterned using this method. This method also requires time for drying so that the solvent phase of the liquid drops (or feathered spray) can evaporate. During the time associated with solvent phase evaporation, the solvent and the material can diffuse
Technologies that use supercritical fluid solvents to create thin films are also known. For example, R. D. Smith in U.S. Pat. No. 4,734,227, issued Mar. 29, 1988, discloses a method of depositing solid films or creating fine powders through the dissolution of a solid material into a supercritical fluid solution and then rapidly expanding the solution to create particles of the marking material in the form of fine powders or long thin fibers, which may be used to make films. There is a problem with this method in that the free-jet expansion of the supercritical fluid solution results in a non-collimated/defocused spray that cannot be used to create high resolution patterns on a receiver. Further, defocusing leads to losses of the marking material.
As such, there is a need for a technology that permits solvent free deposition of a marking material that produces multiple spectral deposits on a receiver.